Norms Establishment of the Diagnosis and Recommendation Intergrated System (DRIS) and Comparison with DOP Approach for Nutritional Diagnosis of Seedless Grape (Sultana, cv) in Western Azarbaijan Province, Iran

Diagnosis and recommendation integrated system (DRIS) and deviation from optimum percentage (DOP) index can be used as efficient methods to interpret the results of plant analysis and the nutritional diagnosis in crops and fruit trees. To establish DRIS norms in seedless grape (Sultana, cv) and compare them with DOP index, leaf samples were collected from 129 vineyards and analyzed for N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B concentrations. The sugar content (brix) of the grape juice was measured as a criterion of yield. On the basis of sugar content, the vineyards were divided into two groups of low and high yielding populations. Standard DRIS norms were established for the different nutrient ratios. DRIS indices were calculated to evaluate nutrients balances and order of nutrients requirements. Sufficiency ranges of macro and micro nutrients were derived by DRIS technique. Means of nutrients concentrations in the high yielding population (high sugar content) were used as reference values for calculating DOP indices. DRIS-derived sufficiency ranges were 2.0-2.8, 0.20-0.27, 1.2-1.7, 1.5-2.1% for,respectively, N, P, K, Ca, and Mg, and 55-138, 40-127, 30-100, 10-20, 30-187 mg/kg for Fe, Mn, Zn, Cu, and B, respectively. DRIS indices showed that, among the macro and micro nutrients in all low yielding vineyards, magnesium and zinc had the most negative index values, respectively. The nutritional balance index (NBI) of DRIS and of DOP (SDOP) were much more than zero in all low-yielding vineyards, indicating that there was imbalance between the absorbed nutrients by grape vines. Comparison of the DRIS indices for the macro and micro nutrients with the DOP indices revealed that Mg and Zn were the most deficient elements in all low-yielding vineyards showing that both methods provide similar information in the interpretation of the results of leaf analysis. To validate DRIS norms and verify the efficiency of DRIS and DOP as methods for improving the interpretation of analysis results of grape leaf, fertilizer experiments should be conducted on seedless grape in a low-yielding vineyard.